Performance tests of a three-element thin-film detector with an analysis of large-scattering-angle charge-state characteristics of germanium and selenium ions

Two experiments have been carried out with the purpose of testing the three-element thin film detector with a surface barrier detector (3TFD-SBD) for use as a nuclear charged particle identifier. The detector consists of a stack of three sequential thin film detectors (TFD's) for measuring the specific luminescence of a transiting ion, and a terminal surface barrier detector for measuring the ion residual energy (Er) after energy losses in traversing the TFD's. The purpose of the two experiments was to develop a better understanding of the advantages of having a three element design and to try to quantitatively relate the performance of a TFD in comparison to other particle detectors. The first experiment tested the detector assembly response to accelerated Ge and Se ions, in the 53 169 MeV range, that were scattered 30 degree of a gold foil target. Various detector characteristics are presented including the ΔL/Δx response of a single detector as a function of the ion velocity and the time resolution of the detector assembly. The second experiment measured the TFD response to 252Cf fission fragments in coincidence with the prompt gamma rays. The nuclear charge resolving power (Z/ΔZ) was determined for a single TFD and the result compared to other nuclear charged particle detectors. In the data analysis of the first experiment, information concerning certain characteristics of the charge states of the scattered ions was revealed. The results were compared to calculated values obtained from two different models that have been used to predict the average charge state of ions after electronic stripping from small impact parameter collisions with neutral targets